Tissure interfolding method and apparatus



Jan. 20, 1953 R. N. SABEE TISSUE INTERFOLDING METHOD AND APPARATUS 6Sheets-Sheet 1 Filed April 5, 1947 fnveni of" Aard'z" 1y: jaz ee Jan.20, 1953 'R. N. SABEE 2,626,145

TISSUE INTERFOLDING METHOD AND APPARATUS Filed April 5, 1947 6Sheets-Sheet 2 R. N. SABEE I Jan. 20, 1953 fn-uenfor 2.71/ 2 ard z jjagee Jan. 20, 1953 R. N. SABEE 2,625,145

TISSUE INTERFOLDING METHOD AND APPARATUS Filed April 5, 1947 6Sheets-Sheet 4 Jan. 20, 1953 SABEE 2,626,145

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Jan. 20, 1953 R. N. SABEE 2,626,145

TISSUE INTERFOLDING METHOD AND APPARATU$ Filed April 5, 1947 -6Sheets-Sheet 6 Si l-dupergo/ilg Jaw/7. Honk af fap pas/712m.

fiez'nAara Z M51668 Patented Jan. 20, 1953 TISSUE INTERFOLDING METHODAND APPARATUS Reinhardt N. Sabee, Appleton, Wis., assignor toInternational Cellucotton Products Company, Chicago, 111., a corporationof Delaware Application April 5, 1947, Serial No. 739,563

11 Claims.

This invention relates to a tissue folding method and apparatus, and itis particularly (but not exclusively) concerned with a method andapparatus for interfolding thin, light-weight tissues of a soft, flimsycharacter having but little tensile strength.

In one form of commercial packaging of facial tissues which are typicalof one kind of material which may be folded, two continuous webs oftissue paper (often having two or more plies) are separately fed betweencutting rolls which sever the webs transversely in such a manner as toleave a few very slight bonds connecting the web portions on oppositesides of the line of severance. Such webs are then fed into face-to-facerelation with the lines of severance of one web in staggered relation tothe lines of severance in the other, after which the sheet areas betweensucceeding lines of severance are folded approximately midway betweenthe lines of severance. Folding is effected in such a manner that thebonds Connecting successive sheet areas of one web are enclosed betweenthe folds of the other web and preferably at the fold line thereof. Theresulting interfolded stack of tissue may be enclosed in a box fromwhich the sheet areas may be successively withdrawn and the leading endof each sheet area automatically pulled out of the box upon withdrawalof the preceding sheet.

In order that only one sheet at a time be withdrawn, it is importantthat the bonds be quite weak so as to be easily broken upon theapplication of a small increment of resistance to withdrawal of the nextsection of the same web, while at the same time being strong enough toavoid breakage merely by reason of the slight resistance createdincident to the pulling of the leading end portion of the other web outof the box. The frailness of the bonds required is such that in mostknown interfolding machinery (much of which is used for interfoldingrelatively strong paper webs such as paper towels) is not operative tointerfold weakly bonded tissue material without breaking the bonds.

The preservation of these bonds is especially important when interfoldedtissue is to be packed in boxes of considerable depth (such as typifiedby facial tissue boxes containing four or five hundred sheets) in whichit is especially desirable that the withdrawal of one sheet shouldautomatically bring to an accessible position, through a narrowdispensing slot, the leading end of the next sheet. Breakage of thebonds would, of course, prevent such automatic feeding of the sheets.This preservation of bond is also highly desirable in connection withthe packaging of continuous Z-folded material Which may be also producedby the method and apparatus to be described.

The main objects of the present invention are to provide a method andapparatus for folding and/or interfolding tissue materials of thecharacter indicated, and to provide a method and apparatus which will beoperative at a very high rate of speed.

Other objects and advantages of the invention will be understood byreference to the following specification and accompanying drawings (5sheets) wherein there is illustrated a folding method and machineembodying a selected form of the invention.

In the drawings:

Fig. 1 is a vertical section through the working parts of the machine;

Fig. 2 is a plan section on the line 22 of Fig. 1;

Fig. 3 is a vertical section corresponding in part to Fig. 1 but takenin a diflerent plane, certain parts being broken away to betterillustrate certain operating details;

Fig. 4 is a more or less diagrammatic view illustrating an arrangementfor driving the various operating parts of the mechanism;

Fig. 5 is a detail view of an element appearing also in Fig. 1, showingmeans for operating one of the shafts of the machine;

Fig. 6 is a section on the line 6--6 of Fi 1 on an enlarged scale;

Fig. '7 is a section on the line 1-1 of Fig. 6,

Figs. 8 to 13, inclusive, are more or less diagrammatic viewsillustrating successive positions of the principal operating elements ofthe mechanism.

As shown in Fig. 1, the machine embodies a unit of mechanism designatedin its entirety by the reference numeral I, said unit embodyingcooperating cutter roll pairs 2 and 3, the roll pair 2' embodying aknife roll 4 and an anvil roll 5 and the roll pair 3 embodying similarknife and anvil rolls 6 and 1', respectively, Paper webs 8 and 9 are fedover suitable guide rolls l0 and l I for the web 8 and a roll l2 for theweb 9 to feed roll pairs l3 and [4, respectively. The feed roll pair [3embodies cooperating rolls I5 and I6, at least one of which ispositively driven at a predetermined rate of speed to effect travel ofthe web 8 at the desired rate of travel. Similarly, the roll pair I4comprises rolls I1 and I8, at least one of whichis positively driven ata predetermined rate of speed to propel the web 9 at the required speedwhich is the same as the speed of travel of the web 8. The rolls of thefeed roll pairs l3 and M are preferably adjustably mounted so as tofacilitate control of the pressure with which the webs fed between themare gripped by the respective roll pairs. The specific means formounting these rolls forms no part of the present invention, and is,therefore, not described in detail.

In the arrangement illustrated, the knife and.

anvil rolls of the cutting roll pair 3 are so set with respect tothe'knife and anvil rolls'of the cutting roll pair 2 that the successivelines of: severance formed in the web 8 will be located substantiallymidway between successive lines of severance formed in the web 9 whenthe webs 8 and 9 are delivered in face-to-face 're'la'tionfroin.

between the anvil rolls 5 and 1 as shown' in Fig. 1.

Commercial forms of facial tissue are usually in the neighborhood of teninches i'n width. It-is convenient to interfold a double width of tissueand to subsequently break the double width into separate sections of therequired width. Accordingly, the apparatus provided with slitters l9'and20-carried on the free ends-of the arms 2 I and-22, respectively, whichare suitably pivotally mounted through the agency of supportingshafts-carried by the frames of the upper unit of mechanism. 7

The slitters I9 and 20 are preferably enclosed by suitable guards 2-3and 24 which are carried by thearms- 2| and-22, and weighted arms 25 and26 associated with-the respective slitter arms 2|- and 22 serve to urgethe slitters i9 and 20 toward the respective guide rolls j-I, and I2with sufiicient force to slit webs 8 and 9 longitudinally intermediatetheir widths. The slitting is not quite complete and does notactuallyseparate the webs into twostrips, suflicient but easily breakablebonding remaining to preserve continuity of the divided webs. 7

The mechanism for Z-folding and for interfolding the paper, is supportedby side framesimmediately below the above-described web feeding,slitting and severing mechanism, The webs tt'and 9 in face-to-facerelation travel downwardly between a pair of folding rolls 21 and--2 8which are carried respectively by shafts 2 9'and'30 which are suitablyjournalled in the side frames 3! and 32, respectively, of the mechanism(see Fig. 2). The rolls 2! and 28 are so-mounted relative to each otherthat their surfaces are spaced apart a distance which will causethe-rolls. to guide the webs 8 and 9 downwardly between them withoutgripping or exerting any positive feeding effect. The rolls arecontinuously rotated in opposite-directions, the roll 21 being rotatedclockwise and the roll 28 counterclockwise as viewed in Fig. 1.

Each of the rolls 2! and 28 carries three sets of jaws and threetuckers, the tuckers being located intermediate the pairs of jaws. Inthe present embodiment of the invention, three-pairs of tuckers andthree jaws are employed, but it is apparent that by using smaller orlarger carrying rolls, or'to adapt the apparatus to the interfolding oftissue sheets of shorter or longer length than those for which thepresent machine is designed, or for other reasons, the number of'jawsand tuckers may be varied.

The r0112! is provided with jaw pairs eachembodying a fixed jaw element33 and a movable jaw element 34. The tuckers provided in the r0112! areindicated by the reference numeral 35, these tuckers being fixedlymounted in the roll. Similarly, the roll 28 has tucker jaws comprisinga. fixed jaw 36, a movable jaw 31- and fixed tuckers 38. The jawsandtuckers extend for the entire length of the respective rolls, but theyare grooved transversely in conformity with the grooves provided in therolls 2'! and 28 for the reception of certain elements which willpresently be described. Certain ofsuch grooves are indicated at 39 and40 in the rolls 21 and 28 respectively, in Fig. l. The movable jaws'34are formed with short shaft sections 4i intermediate the lengths. of thejaws and at their ends. The jaws are rockably positioned in grooves 42in the body of the roll 21. Similarly, the movable jaws 3? of the roll28 are provided with intermediate and end shaft sections 43, and grooves"44 in the roll receive the jaws. The intermediate shaft sections 4! and43 are located in alignment with the grooves 39' and 40 and in therespective rolls and are seated'in bearing surfaces prepared for thatpurpose. Bearing caps 55 and it bolted to the rolls 21 and 23 over thejaw shaft sections hold the jaws in place.

The "end shaft sections 42 and 43 which project beyond the ends of the:rolls are provided with arms which carry rolls at their free endsfor-engagement with cams whereby the jaws may be rocked in predeterminedsynchronism with cooperating elements of the mechanism. One of thecam-operating mechanisms is shown in Fig. 2 wherein the projecting endshaft 4| of the r9112! is shown as being provided with an arm 4?. Thearm 4! is provided at its free end with a roller 48 for engaging theinternal cam surface 69 carried by a cam body 56 which is rota-tablyadjustably mounted as indicated at 5! in theframe 3! in co-axialrelationship to the shaft/29 o f'the roll 21. The roller 48 is urgedinto engagement with the cam surface-Q9 by means of a spring '52 (seeliig. 3) compressed between spring seats '53 and 54, the spring seat 53'being fixedly mounted on the member 56 which is fastened on the end ofthe roll, and the spring seat 54 being carried by the free end of thearm B8) To prevent the accumulation of lint andother foreign material onthe surface of the cam 49, the space between the end of each roll andits associated cam is closed by means such as circular housing elements'55 which are bolted or otherwise secured to the adjacent ends of thecam bodies 5i, and said roll endmembersiifi which have flanges "5 spacedinwardly from the housings 5.5. The space between the housings '55' andflanges '5 is sealed by suitable pacli-ing rings such as representedat'58.

As shown in Fig. '1, the rolls '2? and '28'with their alternate jawpairs and tuckers are so related to eachother that each tucker and oneroll cooperates with a pair of jaws of the other roll. 'Iihe arrangementis such that-each tucker tucks the webs 8" and "9 of tissue into theopposite or cooperating jaw pair while the jaws are open, the tuckerbeing also fully withdrawn from between'the jaws beforethey close andbefore the jaws actually grip the tucked in webs. This method of'ope'r'ation is dear-1y illustrated in Figs. 8" to 13,ino1usi ve, inwhich Fig. 3 illustrates the positiono'f a'tucker and its cooperating'jaw'pair at about the time of fi'rst contact 'thereof'with the web tobe folded (or the webs to be interfolded). In the present embodiment,this po's'iticn occurs when the'point of the tucker 38 is located inregistry with a radius extending upwardly at an angle ofa b-out' 12 froma horizontal radius of the roll.

Figs. '9 and 10 show succeeding positions and correspondingwebpositions, Fig. Q'r'epres'enting a position in which the point of thetiic'keris'i'n registry with a radius extending upwardly at 'an angle of6 from a horizontal radius of the roll 23, and Fig. 10 representing thecondition in which the tucker point is in registry with the horizontalradius-of the roll 28'. It may be observed that the axes'of therolls'2'T and '28 are in the same horizontal plane.

In the tucker positionshown in Fig. 10, ithas,

of course, reached its position of'greatest pene- {ration between thejaws 33 and 34.' The subsequent travel of the tucker results inwithdrawal thereof from between the jaws as clearly shown in Figs. 11 to13. Fig. 11 shows the tucker position in which the point of the tuckeris in registry with a radius of the roll 28 extending downwardly at anangle of 6 from the horizontal radius. In that'position the tucker pointis still between the jaws, but it will be observed that the jaws havenot yet closed and that the web is not positively gripped either betweenthe jaws or between either jaw and the tucker.

Fig. 12 shows a further advanced position of the tucker and jaws inwhich the point of thetucker registers with a radius of the roll 28extending downwardly at an angle of from the horizontal, the tuckerbeing there completely withdrawn from between the jaws, and the movablejaw in a position nearer to the stationary jaw 33 but not yet fullyclosed. In other words, the tucker has completed its operation oftucking the web between the jaws and has been withdrawn from betweenthem without the webs having been gripped between the jaws or betweeneither jaw and the tucker. As represented in Fig. 13, the jaws haveclosed and the tucked-in portion of the web is effectively grippedbetween the jaws. This position results from a further movement ofapproximately 2 downwardly from the position represented in Fig. 12.

In order that the movable jaws shall require a minimum amount of travelfrom open to closed position, the tucker is made with its rear face at aslight angle to a roll radius which passes through the point of thetucker. The angle may vary somewhat and is here shown as being about 7rearwardly with reference to the direction of travel of the tucker androll. The fixed rear jaw which cooperates with the rear face of thetucker approaches said tucker face quite closely during the tuckingoperation but does not come close enough to pinch the paper web (orwebs) against the tucker. The front or movable jaw is initially spacedfrom the more angular front face of the tucker a greater distance thanthe rear jaw is spaced from the rear face of the tucker but graduallyapproaches said front face merely as an incident to the rotation of therolls and without imparting any closing movement to the jaw about itsaxis of pivotal movement. Pivotal movement of the movable jaw, effectedby the cam arrangement already described, is effected during arelatively small travel distance; such jaw pivoting begins at about thetime that a cooperating tucker and jaw pair are centered on a horizontalline extending between the axes of the rolls 2'! and 28, proceedsgradually so as to avoid any pinching of the web against the face of thetucker and is not closed to grip the web against the fixed jaw until thetucker is completely withdrawn as shown in Fig. 13.

For practical reasons, the jaw closing movement is effected over about10 to degrees of roll travel although it would be desirable to completesuch movement in a shorter distance, i. e. almost instantaneously afterthe tucker is withdrawn. Such instantaneous movement, at high operatingspeeds, is practically impossible of attainment without resorting tocostly, delicate mechanism which would not be practicable in aproduction machine such as is being described.

After the jaws are closed, they remain closed until the gripped web foldis just about over the edge of the stack in which the folded material isdeposited. The pivoted jaw is then opened at a speed'which is somewhatfaster than its closingspeed, for example, in about 5 to 10 degrees oftravel, the opening being so timed that the web fold may be dischargedat the proper time as hereinafter explained, the discharge beingeffected even before the jaws reach their fully opened position. Thedischarge of the folded web from a pair of jaws is represented in Figs.8 to 13, inclusive, in respect of the jaws of the roll at the right handside of the figures.

The jaws 33 and 34 (and the jaws 36 and 31) are preferably tipped orfaced with material which offers a significant degree of frictionalresistance to movement of the webs across the surfaces of the jaws. Inone operative embodiment of the invention, these jaws are formed ofsynthetic rubber (neoprene) having a value of approximately 60-62 asdetermined with a Pusey 8; Jones plastometer, the measurement being madewith a inch ball and a load of one kilogram. Such rubber has aresiliency roughly similar to the resiliency of ordinary automobile tiretread rubber. The employment of the rubber jaws in the arrangementdescribed permits the tucker to force the web between the jaws withoutdifliculty while at the same time having the apparent effect ofpreventing the web from following the tucker from between the jaws eventhough the web is not positively gripped between the jaws until afterthe tucker is completely withdrawn. When the web is tucked between jaws,the web is forced into frictional engagement with the jaw tips ratherthan with the meeting faces of the jaws, and the web is not drawn tautaround the edge of the tucker or between the tucker edge and the jawtips. Instead, the web is rather gently bent into a smooth curving loopbetween the jaws and no sharp creasing or folding occurs until the jawsclose on the web as above explained.

Tautness of the web during the tuckin operation is prevented by (a)causing the web feed rolls to deliver the web (or webs) to the foldingroll at a speed which is slightly greater than the normal surface speedof the folding rolls so as to develop a slight amount of slack in theweb length extending from the anvil rolls 5 and I to the folding rolls2'! and 28, and (b) by so spacing the folding rolls 2'! and 28 that theweb is free to slip between them incident to the higher feed rate of theweb as compared with the travel of the jaws and roll surfaces. slippageof the web between the rolls while a jaw pair is carrying a tucked-inweb portion downwardly results in the production of slack as indicatedat S in Fig. 8. By providing slack both above and below the foldingrolls, the tuck may easily be formed without drawing the web tight overany of the engaged jaw and tucker surfaces or edges. Also, the provisionof frictional material jaw tips such as the resilient rubber members,aids in avoiding withdrawal of the tuck incident to withdrawal of thetucker and also aids retention of the tuck for a short time afteropening of the jaws is started, whereby the web is more effectivelypulled fairly taut over the top of the previously delivered stack offolded material.

By inspection of Figs. 8 to 13, inclusive, it will be seen that the webmaterial required to form the tucked-in loop is obtained by taking upthe incoming web slack resulting from the foregoing provision (a), andby pulling up on the web to take up some of the slack resulting from theaforesaid provision (b). By taking up the incoming slack, accumulationof web material immediately ahead of the folding rolls is preventedamams 7. and tensioning of the incoming nii'aterial is avoided'becaus'eof the freely available slack S from which is drawn that portion of thematerial required to form the tucked-in loop .wh'ieh is in excess of theslack freely available from-themc'oming web portion. Possibly, mostof'the'tu'ck material is drawn from the slack below the folding rolls,but in any eventthe tucki s for-med by taking up slack material, therebyavoiding tensioning of any portion' of 'themateri'al. It should beobserved that the slippage of'the web between the folding rolls isslightly resisted by the roll surfaces so that the web does not dropdown between the rolls as fast asit is delivered by the feed rolls;therefore, slack is 'produced bothabove and below the folding rolls.

The interfolded webs are delivered to a stack located immediately belowthe rolls '2! and 28, such stack being formed between guide posts orfingers 9 and '66 which are supported at their lower ends on transverserods '61 and 62. The rods BI and 62 are carried by bracket memberssuchas 63 and 64' which are fastened to the side frames of the machine. Thestack guide members 59 and 68 respectively, extend upwardly intosuitable grooves '67 and 58 in the rolls 21 and 28, there being asufficient number of these guide members 59 and 60 spaced across thelengths of the rolls to adequately support the tissue stack as shown inFig. 1 (see also Fig. 2). The guides 59 and 6b are, in effect, extendeddownwardly by tissue channel-forming plates 69 and 10, which are alsosupported by attachment to the said brackets 63 and '84. The pl'ate'lfl'is extended 'forwardly at an angle as indicated at ll'to'form the topwall of a horizontally and downwardly extending chute or channel, thebottom wall of which is formed by the upper reach of a conveyor belt 12.The guide plate 69 terminates a short distance above the conveyor belt12 as shown. The belt 72 is normally driven at a very slow rate of speedapproximately corresponding to the rate of travel of the stack oftissues resulting from the addition of folded sheet after sheet to thetop of the stack and down: ward feeding of the stack top by strippingand hold-down devices presently to'be described.

The belt 12 is driven from a pulley 73 (Fig. 1') carried by a shaft '54which is suitably journalle'd in the frame structure of the machine. Ata suit able point in the length of the shaft l4 it has secured to it aclutch disc 75 (see Fig. 5) which is surrounded by a clutch ring it. Theclutch ring 16 is rocked and has an operativeconnection to the clutchdisc 75 of such character that when the ring 16' moves'in one direction,the disc and shaft M will be advanced while 'movement of the ring '56 inth'e'opposite direction will be independent of any movement of the disc15 and shaft #4. Any suitable one-wayclutch' may be employed, and inthis instance, it is represented as constituting a ball type of clutchembodying one or more balls or rollers Tl housed in recesses such as 15in the disc 15 and grooves such as 79 in the ring it. The bottoms of therecesses 18 are so related to the circumference of the disc that whenthe ring IS-turns in one direction, the balls will become'wedged betweenthe bottoms of the grooves 79 and the bottoms of the recesses i8 so asto effect unitary movement of the ring E6, the clutch disc '75 and -shaft 14. Movement of thering in the other direction serves, of course, torelease the clutch-- ba1ls or rollers so that reverse movement of thering i6 is not imparted to the disc and'shaft 14.

The ring 76 is-provided with an arm an (see Fig. l) which is slotted toadjustably receive a pivot block 81-. Thepo'sition of the'plvot block 8the slotted arm maybe adjusted-and hired by any suitable ineanssu'chasanadjusting screw 82 and a lock 'nut 83'to thereby facilitateadjustmentof the amount of travel imparted to the belt by each operative movementof the clutch ring. Rocking motionis imparted to' the I arm '81 by meansof anecceritric- 8 carried by a shaft 85 suitably journall'e'd in theIna-chine frame. An eccentric ring 86' surrounds the eecentric 84 andconnected to the clutch' a'rrr'i'81] by means of ename formed integrallywith the ring and pivoted to the block 81.

The shaft 85 is continuousl yrotated by a suitable driving connection,one of which will-herein after be explained.

The jaws -33 and 34- o'fthe roll 2 and the jaws 36- and 3"! of the roll28 serve to alternately deposit-web folds at the opposite sides of thestack. To insure stripping of the folds from the jaws which areautomatically opened as they approach the vertical planes of the frontand rear sides of the stack, there are provided a plurality of stripperarms 88 and as respectively associated with the rolls 2? and 2 8,thegrooves 3'9 and 4d previously referred to,-serve to receive suchstrippers in their elevated positions. The strippers 8'8 and- '89 arecarried respectively by shafts 9i] and SI which are suitably'journaledin the side frames of the machine and these shafts together with theirstrippers are rocked in properly timed relation-to the travel of thejaws of the respective rolls so that the end or finger portions 881; and89a of the respective-strippers will be'operative to strip the foldedwebs'from the jaws of the respective rolls and pack the folded web downon top of the stack of folded tissues.

The shaft 96 is rocked by means of an arm 9-2 which is carried by theshaft 90 and connected by means of a pin and slot-connection to an arm93 which has "an eccentric ring 94 surround ing an eccentric'disc"9 5'-carried by a driven shaft 96. The shaft 9| is rocked by similaroperating connections to an eccentric 91 carried by a driven shaft 98.'The pinand slot-connectionsinthe arms serve to permit adjustment ofthe" throw of "the stripper fingers 88a and 89d and their timing may beadjusted by adjustment of the eccentric discs '95 and '97 about theshafts 9'6 and 98. In addition, the arm 92 on thesh'aftti) and itscounterpart on the shaft .91 maybe adjustably connected to the shaft topermit ad'- justment'of the positionof there'spective strip per'fingers.

When one of the "strippenfin'ge'rs 588a or 89a is'in a down position (inwhich the stripper'8'8a' is illustrated in Fig. 1) the' other stripperis in an elevated position. Also, the stripper fingers have anintermediate position in which they are both located about midwaybetween their upper and lower positions; In order toholdthe topof thestack against upward displacement when the stripper fingers 88a and-89aare in elevated relation to thenormal-top -levelof the stack there areprovided holding arms or-hooks 99 and I00 respectively-carriedby shaftsNH and [92 which are rockably mounted in the f-ramesid'es of themachine. The-arms 99 and idii'areprovided at their upper ends with headsHl-3-and-- Hi4 respectively which move from aposition" overlying; therespective margins of thestack toretracted p0 sitions r'clear 0f the topareacof the stack. :In their "retracted positions the" heads ofthe'holddown arms are received in the aforementioned grooves 39 and 40at the sides of the respective stripper fingers 88a and 89a as indicatedin Fig. 2. The hold-down arms 99 and I50 are secured to the shafts IIIIand H32 which are rocked in such synchronism with the movement of thestripper fingers that the hold-down members are brought into operativeengagement with the top of the stack before the associated stripperfinger leaves the top of the stack. Therefore, the top of the stack isat all times restrained against upward movement beyond a desired level.

The shafts IOI and IE2 may be rocked in the required timed relation tothe operation of the strippers by any suitable means, such as typifiedby cams I85 and I06 carried by a frame carried stub shaft represented atN31. The cams are rotated by a suitable connection to one of the otherrotating parts of the machine whereby the proper timed relationship willbe maintained. The cams I and H16 respectively act against rollers carried at the free ends of arms I08 and I09 which are respectively securedto the rock shafts IIH and I02.

The arrangement is such that the top of the stack of interfolded sheetsis located very close to the surface of the folding rolls whereby thefolded web can be deposited on the top of the stack with a minimum oftravel time. B maintaining the top of the stack very close to thesurface of the interfolding rolls, the extent of movement required to beimparted to the stripping fingers and to the hold-down members is keptat a minimum whereby high speed operation of the machine is greatlyfacilitated. The top of the stack is so close to the surfaces of thefolding rolls that light contact may occur where the stack bulgesupwardly between adjacent strippers and hold-down hooks. The angularpositicns of the tuckers and the leading jaws are such that these partsmore or less cam the stack top downwardly incident to their passage overthe stack without applying any adverse sidewise force to the stack.Apparently, because of the high speed at which the rolls rotate, thestack does not have time to expand upwardly into the path'of thetrailing jaw.

Crepe tissue wadding and other material of the character which may befolded or interfolded bythedescribed apparatus is apt to varyconsiderably in bulk incident to changes in atmospheric conditions.Under some conditions the tissue webs will have considerably greaterbulk than under other conditions. Manufacturing processes may also havea bearing on the variation in the bulk of the crepe tissue which isdelivered to the folding machine and this variation in bulk may occurwithin each separate runor roll of tissue delivered to the interfoldingmachine. These variations in bulk, especially an increase in bulk, willtend to alter the level of .the top of the stack. While the level cannotaotually be altered due to the positive action of the strippers andhold-down members, the variation 'does tend to create such expansiveback pressure in the stack of folded tissues that normal operation ofthe strippers and hold-down fingers at high speeds is hampered.

The normal'feed of the stack of interfolded tissues by the conveyor belt12 can easily be designed to handle the tissues when deliveredconstantly under their minimum bulk conditions.

However, when the bulk is increased the normal stack feed produced bythe belt "I2 will be slow -with the result that the stack tends toexpand at its top or receiving end. To prevent establishment of theindicated back pressure and thereby to maintain normal workingconditions for the strippers, means have been provided for acceleratingthe speed of travel of the conveyor belt I2 when back pressure of thetop of the stack requires it. This means is completely automatic.

The control means for accelerating the rate of travel of the stackfeeding belt I2 consists in the provision of pressure sensitive stripperarms adjacent the ends of the roll 28 in place of normal stripper arms,such as represented by the arms 89. The pressure sensitive stripper armarrangement (shown in Fig. 3) consists of a main arm portion I Illmounted on the shaft 9| so as to rock as a unit with the normal stripperarms 89. The arm IIO has a supplemental arm III pivoted on it asindicated at II2, the supplemental arm extending in opposite directionsbeyond the pivot H2. The inner end of the arm III is provided with astripping finger IIIa which corresponds to the stripping fingers 89a andthe opposite end of the arm III is provided with an adjustable screw II3which is adapted to actuate the control pin I I4 of a suitable electricswitch I I5 which is mounted on a downward extension of the main armIII). The screw II3 actuates the control pin of the switch through theagency of a flat leaf spring IIB so that great accuracy is not requiredin the matter of aligning the screw H3 and control pin H4 of the switch.A suitable tension spring II? is anchored at its upper end to the top ofthe arm III, extends downwardly through a hole in the arm and isconnected to an adjusting screw H8 which is threaded through a lug H9 onthe arm H0. The spring I I1 serves to normally hold the supplemental armI I I seated on the edge or seat I2I] of the main arm III]. The tensionof the spring II'I may be adjusted by appropriately adjusting the screwI I8.

In the event that the stack of tissue begins to offer excessiveresistance to the normal downward movement of the stripper fingers tothe plane of the top of the stack, the arm III will be caused to rock onits pivot II2 against the tension of the spring I I1. Such rockingmovement will close the switch H5 and thereby establish an electriccircuit which controls an electric motor I2I (Fig. 1) which is employedfor driving th conveyor belt I2 independently of and in addition to thenormal drive of the belt as already explained. The electric circuitclosed by the switch H5 is suitably connected to a time delay relay I22which may be any one of many suitable constructions, many of which arecommercially available. The time delay relay I22 serves, each time it isactuated, to close for a definite time period, an electric circuit'to amotor starter I23 which is suitably electrically connected to the motorI2I. Hence, each time that the switch H5 is closed, the motor I2I willbe actuated for a predetermined time period during which, throughconnections about to be described, the tissue stack feed belt 12 will beadvanced. This time interval during which the motor I2I is operated maybe any time interval which experience indicates to be desirable, forexample, two or three seconds.

The motor I2I operates through a suitable speed reduction meansindicated generally at I 24 to drive a sprocket I25. A chain driverepresented at I26 from the sprocket I25 to a shaft I21 serves to effectrotation of a worm gear I28 on the shaft I21. Said shaft I2! is suitablyjournaled ina bracketmember we provided. for that purpose and the wormgearv I28 meshes with aworm wheel I 36 which is rotatably. mounted onthe shaft 74; Rotation of the worm wheel I30 when'driven'by the motor I21, is imparted to the conveyor driveshaft 14 through the. agency of apawl. I3-I carried by the worm wheelianda ratchet I32 which is pinned orkeyed to theshaft T4. The pawl I-3I is springpressed into engagementwith the ratchet 32 and it is faced in. such a direction that when theworm wheel I36 is driven by the motor I2 I rotation will be imparted tothe shaft Id-while rotation of the shaft 'M'may be imparted fromthe-normal driving shafts already explained without tending to drive theworm wheel reversely;

Each time that excessive back pressure: developsin the receiving end ofthe tissue stack, one or both of the pressure sensitive stripper fingers(there being one at each end-of thefolder roll 28), will be actuated toproduce the described accelerated feed of the stack to thereby relievesuch pressure. Hence, the development of suflicientbackpressure tointerfere with normal operation of the strippers and: hold-down fingersis-no't permitted to develop I As shown inFig. 2, there isa grooveorrecess in. the middle portion of each-of the rolls Z'IJand 28- whichis approximately twice the width of theg-rooves 35 for receivingthenormal stripper fingers 89 and'the pressure-sensitive stripperfingers M In. These enlarged grooves receive stripper fingers 88b and fib-whic'h are widened as compared with thenormal strippers sta and t'iiaso as to extendwel-l beyond bo-th sides of the longitudin-al slit in theinter-folded Webs. This provision ofwidenedfingers avoids thelocalization of pressure near the longitudinal slit; distortion of thewebs at the slits which would tend to break the remaining bond isthereby avoided.

One arrangement of 1 driving connections for the various parts of themachine is illustrated in Fig. 4. For drivin purposes one of the shafts29cr-3iil='may be driven by; a suitable chain drive connection to anelectric motor, this primary drive beingnotshow-n. The shafts 2-9 and 3Bare geared together bygears represented at I33 and t3 l'secured to therespective shafts 29 and 30. The shafts fi-and 98 may be driveninproperly timed relation to the drive of the interfolding rolls bymeans of gears represented-at I35 and Ifitcarried by the respectiveshafts 96 and 98 and meshing withthe gears I 33 and I35 respectively.For driving the shaft 85- from which the normal feed of the tissue stackis obtained, there may be: provided a chain drive represented at I3'Ifrom a suitable sprocket mounted on the roll shaft 29" to I engage asuitable sprocket mounted on'the eccentricshaft 35; The hold-downactuating cams which are carried by the shaft I01 may also be driven byachain I38 which engages suitablersprockets carried by therespectiveshafts 30 and. IN; a

The shafts I39 and MIlpf the cutter roll pair 3 and the shafts MI andI-4Z of the cutter roll pair 2' may-be driven by means of' an idler gearI43 whichmeshes with a gear I ion theinterfolder roll shaft '29 andagear' M on the cutter roll shaft I40. The gear I45 meshes with anothergear MB on the knife roll shaft I39 and with a gear I41 on the cutter;roll shaftMLsaid gear I41 also meshing with. a gear I48- on the cutterroll shaft MI. The innermost rollsiof the web feedroll pairs I3 andMmay'be drivenifrom therespectivelyadjacent gears I45 and. IA! oftheanvil rolls through its release from the folding jaws;

the agency of gears; M9 and I50 secured to the respective feedrollshafts and meshing with the respectively adjacentanvil roll gears I andI41. The outer. rolls I5 and I8 of the tissue feed r011 pairs maybefrictionally driven from theinner rolls, saidouter rolls being arrangedto. gravitate toward the driven inner rolls or provided with springmeans urging, them toward said inner rolls. Thegears and sprockets forthe chain drives are, of course, properly selected as to their pitchdiameters and number of teeth to produce the required rotation of thevarious driven parts.

The described machine is operable. at much higher speeds than haveheretofore been attained in folding machines of the general characterdescribed. Operation at a speed to produce 800 folds per minute (400folds at each side of the stack) is entirely feasible and practical, andit appears that some increase may be anticipated.

Some of the main factors which make possible this high speed operationcomprise the simplification ofthe folding rolls to employ fixed tuckers,and gripping jaw pairs embodying only one movable jaw with attendantsimplification of operating mechanism; the avoidanc or elimination ofsnap action mechanisms facilitates said high speed operation with aminimum of shock and strain on the machine andthe web, thereby attainingdurability of the machine, freedom from breakdowns of the machine andthe web, and quietness of operation; the free and untensioned webarrangement which permits the tucks to be made in the described mannerwithout pulling the web taut at any point whereby bond breakage isavoided; the use of rubber friction tips to control the tucked-in web,i. e. to prevent withdrawal of the web by the tucker incident toretraction of the latter from between a pair of jaws; the use of saidfriction jaw tips to aid in retaining the folds in the jaws againstpremature discharge therefrom upon being opened, even though opening ofthe jaws is started in advance of the desired point of fold dischargethenearly radial or sharply inwardly folded position of the folds betweenthe jaws probably also helps to insure web fold retention in the jawsufficiently to draw the deposited web smoothly across the stack withoutalso pulling the web from under the stripper or hold-down fingers at theopposite side of the stack; the resilient character of the jaw tipswhich permits the jaws to cometightly together to grip thewebs withoutrequiring extreme, if not practically unobtainable, accuracy in respectof the'size and extent of movement of the movable jaws in apparatusdesigned to operate at the indicated high speed; positioning of the topof the stack of folded material close to the folding roll surfaces so asto reduce the extent of travel required of the strippers and of thefolded web upon and maintenance of a substantially constant pressurereaction of the folded stack on the stripper fingers. There are perhapsother factors, but those mentioned are probably the most important.

In the arrangement described, thetuckers and jaws are so related thatthey do not pinch the web between them; in some instances, it'may bedesirable that one or the other of the jaws be so related to the tuckeras to more or less brush or wipe the web from the tucker incident torecesfled by: (a) tissue paper having a dryer basis weight of about 7.64pounds per ream (480 sheets) 24" x 36"; (b) said tissue paper (a) aftercreping so as to have a basis weight of about 10.5 pounds per ream ofsheets 24" x 36"; and double ply creped tissue paper such as used formaking commercially available facial tissues, the basis weight for suchdouble ply material being about 19.1 pounds per ream of 480 double plysheets 24" x 36". These basis weights are set forth merely as typical ofthe kind of light-weight and flimsy material which can be successfullyfolded and interfolded; limitation of operativeness to these weights isnot to be implied from this recitation.

Various changes in the described apparatus may be made, and theapparatus may be employed for either Z-foldingor interfolding purposes(this depending on the number and arrangement of webs fed to the foldingrolls), while retaining the principles of the invention. In thefollowing claims, reference to Z-folding will, of course, includeinterfolded sheets as produced by the described apparatus since theinterfolded sheets include, in effect, two Z-folded webs.

I claim:

1. In a rotary folding machine of the class described, the combinationof a pair of folding rolls mounted for rotation in opposite directions,means for feeding a web to be folded to said folding rolls, a pair ofjaws and a tucker carried by each of said rolls, means for driving saidrolls in such timed relation that the tucker of each roll enters betweenthe jaws of the other and is withdrawn therefrom as an incident to therotation of the rolls, means independent of said tucker for holding thejaws in spaced, nongripping relation to the cooperating tucker when thelatter is disposed betwen the jaws and for causing said jaws to closeand grip the tucked in web material immediately following withdrawal ofthe tucker from between the jaws, and means for subsequently reopeningsaid jaws to discharge the tucked in material.

2. In rotary folding mechanism of the class described, the combinationof a pair of oppositely rotatable rolls, means for delivering a paperweb between said rolls, each of said rolls being provided with a pair ofjaws and with a tucker, one of said jaws being movable relative to theother to open and close the jaws and the tucker of each roll beingadapted to cooperate with the jaws of the other to tuck the web betweenthe jaws, and cam means for controlling the opening and closing of saidjaws and arranged to maintain said jaws in open position to freelyreceive the tucked in web without gripping the web between the jaws orbetween either jaw and the tucker and to effect closing of said jaws togrip the tucked-in web portion immediately following withdrawal of thetucker from between the jaws.

3. In a rotary folding machine of the class described, the combinationof a pair of rotatably mounted folding rolls, means for rotating saidrolls in opposite directions, means for delivering a web of material tosaid rolls, a pair of jaws and a tucker carried by each of said rolls insuch relationship that upon rotation of the rolls, the tucker of eachroll is operative to tuck said material between the jaws of theother,said jaws being operative to grip and carry the tucked-in material, saidweb-delivering means being actuated so as to deliver said web at a rateof travel which is greater than the rate of travel of said jaws and saidrolls being spaced from each other sufficiently to permit the web toslip between the rolls at a rate of travel which is greater than saidrate of jaw travel, thereby to produce slack in the web portionextending from a pair of jaws which are carrying said tucked-in webportion and the zone in which said tuckers tuck the web into the jaws,whereby material required in said tuck is freely available from saidslack without tensioning the web.

4. In a rotary folding machine of the class described, the combinationof a pair of rotatably mounted folding rolls, means for rotating saidrolls in opposite directions, means for delivering a web of material tosaid rolls, a pair of jaws and a tucker carried by each of said rolls insuch relationship that upon rotation of the rolls, the tucker of eachroll is operative to tuck said material between the jaws of the other,said jaws being operative to grip and carry the tucked-in material, saidweb-delivering means being actuated so as to deliver said web at a rateof travel which is greater than the rate of travel of said jaws and saidrolls being spaced from each other sufficiently to permit the web toslip between the rolls at a rate of travel which is greater than saidrate of jaw travel but less than the rate at which said material isdelivered to said rolls, thereby to produce slack in the web portionextending from a pair of jaws which are carrying said tucked-in webportion and the zone in which said tuckers tuck the web into the jaws,and between the web receiving side of said rolls and said deliveringmeans, whereby material required in said tuck is freely available fromsaid slack without tensioning the web.

5. In a rotary folding machine of the class described, the combinationof a pair of rotatably mounted folding rolls, means for rotating saidrolls in opposite directions, means for delivering a web of material tosaid rolls, a pair of jaws and a tucker carried by each of said rolls insuch relationship that upon rotation of the rolls, the tucker of eachroll is operative to tuck said material between the jaws of the other,said jaws being operative to grip and carry the tucked-in material,means for controlling the opening and closing of said jaws and arrangedto maintain said jaws in open position to freely receive the tucked-inweb without gripping the web between the jaws or between either jaw andthe tucker and to effect closing of the jaws to grip the tucked-in webportion immediately following withdrawal of the tucker from between thejaws, said web delivering means being actuated so as to deliver said webat a rate of travel which is greater than the rate of travel of saidjaws and said rolls being spaced from each other sufiiciently to permitthe web to slip between the rolls at a rate of travel which is greaterthan said rate of jaw travel, thereby to produce slack in the webportion extending from a pair of jaws which are carrying said tucked-inweb portion and the zone in which said tuckers tuck the web into thejaws, whereby material required in said tuck is freely available fromsaid slack without tensioning the web, and said jaws being provided withfriction material tips which serve to resist slippage of the tucked inmaterial out of the jaws during withdrawal of the tucker from said jaws.

6. In a rotary folding machine of the class described, the combinationof a pair of rotatably mounted folding rolls, means for rotating saidaccrues rolls in oppositeudirections, means for; delivering aweb: ofmaterial to saidwrolls, av pair of. jaws and a -tucker carried by each.of saidrolls in. such "relationship thatupon rotation of 'the:;rolls,the tuckerof each roll is operative. to tuck said .material between thejaws of the other, said jaws being. operative to gripand carry thetucked-in material, means for controlling the opening and closing ofsaid jaws and arranged to maintain said jaws in open position to freelyreceive the tucked-in web without gripping the web between the-jaws orbetween either jaw and the tucker and 'to :efiect; closing of the jawsto grip the tucked-in. web portion immediately following withdrawal ofthe tucker from between the jaws, said web-delivering, means beingactuated so as to, deliver said web at a rate oftravel which is greaterthan the :rate of travel of said jaws and .said.rolls ,beingspaced fromeach, other sufiicient- 1y 'to permit the web to slip between therollsat a, rate of travel which is greater than said rate of: jaw travel butless than the rate at which said material is delivered to said rolls,thereby to-produce slack in the web portion extending from, a pair. ofjaws which are carrying said tucked-in web pprtionand'thezone in whichsaid tuckers tuck the web into the jaws, and between the web receivingside of saidrolls and said delivering means, whereby material requiredin said-tuck isfreely available from saidrslack withouttensioning theweb, and said jaws being provided with friction material tips whichserve to resist slippage of the tuckedein material out of the jawsduring, withdrawal of the tucker from said jaws.

7-. In: the art of Z-f-olding a weakly bonded transversely slitted webbyapparatus embodying travelling gripping jaws and a travelling tuckerwhich tucks the web between the jaws-during predetermined, cooperatingportions of' the paths of travel of said jaws and tucker, the step ofproviding free slack in the web between said cooperating portions ofsaidpaths of travel and a tuck in theweb carried by a pair of jawsimmediately beyond said cooperating portions, thereby to provideavailable free material for the tuck in the web so as to avoidtensioning of the material'and breakage'of: said bonds. incident to thetucking of the web as' aforesaid.

8. In th art of Z-fOldiIlg a weakly bonded transversely slitted web byapparatus embodying. travelling gripping jaws and a travelling tuckerwhich tucks the web between the jaws during predetermined, cooperatingportions of the paths of travel of said jaws and tucker, the .step ofproviding free slack in the web in both directions from said cooperatingportions of said pathsof travel, thereby to provide available freemateriaifor the tuck in the web so as to avoid tensioningofthe materialand breakage of said bonds incident to the tucking of the webasaforesaid.

9. In the art of Z-folding a weakly bonded transversely slitted web byapparatus embodying travelling gripping jaws and a travelling tuckerwhich enters between said jaws and is retracted therefrom to tuck theweb between the jaws during predetermined, cooperating portions of thepaths of travel of said jaws and tucker, the. steps of providing freeslack in the web in at least one direction from said cooperatingportions 10f? aid pathsofvtrav i. h r y to; provide available,free-matsrialfor the tuck in thegwebso as: tel-avoidrtensijoning of thematerial and breakage. of said Ebonds incident to the tucking: of theweb asgafgoresaid, maintaining said jaws out of web grippingrelationship to said tucker during said'cooperative portions of thepaths of travel of' said jaws and tucker, and after said tuckerisfretracted, closing the jaws to grip the tucked in portions of theweb.

1,0. In the art of Z-folding a weakly bonded transversely slitted web,by apparatus embody ing; travelling gripping jaws and a travellingtucker which enters; between said jaws and is retracted therefrom totuck the web between the jaws during predetermined, cooperatingportions, of the paths of travel of said jaws and tucker, the'steps ofmaintaining said jaws out of web gripping relationship to said tuckerduring said cooperative portions of the paths of travel of said jaws andtucker, and after said tucker is retracted, closing the jaws to grip thetucked-in portions of the web.

11 In a rotary folding machine of the class described, the combinationofa. pair of rotatably mounted folding rolls, means for delivering a webofmaterial to said rolls, a pair of jaws and a tucker carried by each ofsaid rolls in such relationship that upon rotation of the rolls, thetucker of each roll is operative to tuck said material between the jawsof the other, said jaws being operative to grip and carry the tucked-inmaterial, means for controlling the opening and closing of said jawsand. arranged to maintain said jaws in open position to freely receivethe tucked-in web without gripping the web between the jawsorbetweeneither jaw and the tucker and to effect closing of the jaws togrip the tuckedin web portion immediately following withdrawal of thetucker from between the jaws, and said web. delivering means beingactuated so as to deliver said web at a rate of travel which is greaterthan therate of travel of said jaws and said rolls being spaced fromeach other sufficiently to .permit the web to slip between the rolls ata rate of travel which .is greater than said rate of jaw travel, therebyto produce slack inthe web portion extendin from a pair of jaws whichare carrying said tucked-in web portion and the zone in which saidtuckers tuck the web into the jaws, whereby material required in saidtuck is freely available from said slack without tensioning the weREINHARDT N. SABEE.

REFERENCES CITED The. following references are of record in the file ofthis patent:

UNIED STATES PATENTS Number Name Date 1,003,446 Gauch Sept. 19, 19111,015,580 Nichols Jan. 23, 1912 1,756,392 Smith Apr. 29, 1930 2,057,879Campbell Oct. 20, 1936 2,246,336 Wyrick June 17, 1941 2,449,663 MarcalusSept. 21, 1948 2,468,254 Deloye Apr. 26, 1949 FOREIGN PATENTS NumberCountry Date 385,107 Great Britain Dec. 22, 1932

